A method of manufacturing a printed wiring board having at least one solder bump includes forming a solder resist layer on a conductor layer. The solder resist layer has at least one opening that exposes a connection pad of the conductor layer, and the at least one opening in the solder resist layer has a depth D, from the solder resist layer to the exposed connection pad, of from 3 μm to 18 μm. The method also includes loading a solder ball into each of the at least one opening in the solder resist layer, and forming a bump on the exposed connection pad by heating the solder ball to a reflow temperature.
Legal claims defining the scope of protection, as filed with the USPTO.
2. The method of claim 1 , wherein the loading includes arranging the solder ball to be in contact with the exposed connection pad before said forming.
3. The method of claim 1 , wherein a diameter of the solder ball is less than 200 μm.
4. The method of claim 1 , wherein said loading comprises: arranging a mask over the solder resist layer so that an opening portion in the mask is aligned with each of the at least one opening in the solder resist layer; positioning a cylinder member having an opening facing the mask; gathering multiple solder balls below the cylinder member by sucking air through the opening of the cylinder member; and moving the cylinder member or moving the printed wiring board and the mask in order to load one of the gathered multiple solder balls into the at least one opening of the solder resist layer through the at least one opening portion in the mask.
5. The method of claim 4 , further comprising: holding the cylinder member in a stationary position on a vertical axis while moving the printed wiring board and the mask in a horizontal plane substantially orthogonal to the axis.
6. The method of claim 4 , further comprising: holding the printed wiring board and the mask in a stationary position on a vertical axis while moving the cylinder member in a horizontal plane substantially orthogonal to the axis.
7. The method of claim 4 , wherein the sucking air through the opening of the cylinder includes sucking air such that a velocity of the air at a gap between a bottom of the cylinder member and an upper surface of the mask is 5 m/sec to 35 m/sec.
8. The method of claim 1 , wherein: said forming comprises forming the at least one opening to have a diameter of 60 μm; and said loading comprises loading a solder ball having a diameter of 70 μm.
9. The method of claim 1 , wherein: said forming comprises forming the at least one opening to have a diameter of 80 μm; and said loading comprises loading a solder ball having a diameter of 110 μm.
10. The method of claim 1 , wherein: said forming comprises forming a solder resist layer having a plurality of openings each having said depth D and exposing a respective connection pad; and loading a solder ball into each of the plurality of openings.
12. The method of claim 11 , wherein a diameter of the solder ball is less than 200 μm.
13. The method of claim 11 , wherein the loading comprises: arranging a mask over the solder resist layer so that an opening portion in the mask is aligned with each of the at least one opening in the solder resist layer; positioning a cylinder member having an opening facing the mask; gathering multiple solder balls below the cylinder member by sucking air through the opening of the cylinder member; and moving the cylinder member or moving the printed wiring board and the mask in order to load one of the multiple solder balls into the at least one opening of the solder resist layer through the at least one opening portion in the mask.
14. The method of claim 13 , further comprising: holding the cylinder member in a stationary position on a vertical axis while moving the printed wiring board and the mask in a horizontal plane substantially orthogonal to the axis.
15. The method of claim 13 , further comprising: holding the printed wiring board and the mask in a stationary position on a vertical axis while moving the cylinder member in a horizontal plane substantially orthogonal to the axis.
16. The method of claim 13 , wherein the sucking air through the opening of the cylinder includes sucking air such that a velocity of the air at a gap between a bottom of the cylinder member and an upper surface of the mask is 5 m/sec to 35 m/sec.
17. The method of claim 11 , wherein: said forming comprises forming a solder resist layer having a plurality of openings each having said depth D and exposing a respective connection pad; and loading a solder ball into each of the plurality of openings.
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May 12, 2008
December 27, 2011
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